The large format maps of the Metropolitan District Railway (London Underground's District Line) were published mainly in the last quarter of the nineteenth century and the first few years of the twentieth.
These are the earliest series of maps produced for the London Underground.
The maps are fascinating but exist in a large number of different states.
This treatise has attempted to publish all that is known about the different states. It is partly based on a number of published but not widely known sources (mainly Garnett and Hyde), and partly on the author's collection or those of his colleagues.
Any errors or omissions that readers may care to point out would be most helpful.
In due course something similar will be produced about other District Railway maps.